I didn't find the gun energy system to be a fun gameplay mechanic.
An early upgrade gives you a recharging shield that soaks one shot every so often. The upgrades are temporary, and taking damage reduces your energy by one level, so you only maintain maximum power if you avoid getting hit. At the max level, you get an incredible powerful wave beam that tears through entire rooms of enemies. One upgrade increases the range, two upgrades let you choose a penetrating laser, three upgrades a machine gun, and so on. Each power-up changes the available weapons rather than its power.
Jason has a gun that powers up with collected energy. The most interesting element of the top-down segments is how your weapon power-ups work. Some of these caves are played in the same 2-D plane, but others change to an isometric viewpoint, so you don't have the ability to jump. While the bulk of your time in the game is spent in Sophia, there are times when Jason goes on foot to explore areas that Sophia can't reach, such as small tunnels or caves. Levels that took a half-hour to get through the first time can be zoomed through in under a minute once you have the correct combination of powers. There's just enough backtracking, so you get a sense of how much Sophia improves in a short time. It's not quite up to the sense of exploration that comes with an actual Metroidvania title, but it feels good and gives the game a solid sense of progression. You'll eventually have to get every power in the game to unlock the final stage. Once you backtrack or get a new ability, it allows you to search for hidden upgrades that are entirely optional but unlock new combat or exploration abilities. The game design is such that each of these abilities leads you to the next plot area, and there's only minimal backtracking. She starts with a cannon and the ability to jump, and she gains the power to scale walls, hover, swim and more. Sophia the tank begins with a handful of abilities but gains more as you progress. It's not quite a free-open exploration, but it's not entirely linear, either. The basic gameplay in Blaster Master Zero is similar to Metroidvania lite. The plot is somewhat more dramatic than the original but adheres to its lighthearted frog-finding roots. Jason and Eve work together to figure out what's causing the mutations that threaten the world. One day, Fred escapes, and while Jason is chasing him down, he discovers an abandoned battle tank named Sophia and a lost girl named Eve. Jason is a gifted researcher who discovers a frog-like organism that he names Fred. Set on a postapocalyptic Earth, Blaster Master Zero is a fusion of the original Metafight and the Americanized Blaster Master.
As the name suggests, it's an attempt to return the franchise to its roots, and it's an unqualified success. Blaster Master Zero, developed by Mega Man 9 and 10 developers Inti Creates, is the first attempt in quite some time.
Over the years, no attempt to revive Blaster Master had much success. The game was memorable for its shifting viewpoints and difficult gameplay. Originally released as the mouthful of a name " Super Planetary War Records Metafight" in Japan, it was localized with a more lighthearted plot for its North American release. It never quite reached the immense popularity of Castlevania or Mega Man, but it was a memorable game. Blaster Master is a cult classic of the NES era.